Women with Rh Negative blood type at high risk of Rh incompatibility related pregnancy complications: Pre-natal Screening Must

Are you a woman with an Rh Negative blood type planning a pregnancy? If yes, then you might be at the risk of experiencing pregnancy related complications due to Rh incompatibility and awareness is critical for you to ensure timely medical intervention. Unfortunately, a large number of Rh negative women susceptible to being affected by RH incompatibility fail to receive preventive treatment due to lack of awareness and paucity of adequate facilities, especially in rural areas.

Rh incompatibility is a potentially dangerous condition that has serious consequences for fetal health. If left untreated, a Rh incompatible pregnancy may end up in a miscarriage or a still birth, apart from posing the threat of fetal anemia, severe jaundice, and even neurological disorders in the new-born. Experts suggest that the estimated incidence of the Rh-D negative blood group in India varies between 3% and 6%. The risk of Rh incompatibility occurs when a woman with a Rh-Negative blood type conceives a Rh-Positive baby.

What happens when an Rh-Negative woman conceives?

When a Rh-Negative woman conceives a Rh-Positive baby, the mother’s immune system can perceive the fetus as a foreign protein and develop antibodies against it. Rh antibodies made in a woman’s body can then cross the placenta and attack the fetal red blood cells with a D positive blood group. This can cause a series of potentially devastating effects. As the reported incidence of Rh sensitization during pregnancy is about 1-9%, all pregnant women must be screened for their blood type and Rhesus status on their first antenatal visit itself. The complications of Rh incompatibility can be prevented with close surveillance of the pregnancy for rising maternal antibodies and fetal health, and timely medical intervention.

The mother’s immune response often ends up destroying the foetal RBCs, resulting in a haemolytic disease of the foetus and new-born (HDFN). This leads to progressive anaemia coupled with hypoalbuminemia (low albumin in the blood) and fetal heart failure (hydrops fetalis), an important cause of still births and early neonatal deaths. Those who survive have a higher neonatal morbidity and mortality as a result of hyperbilirubinemia (high bilirubin in the blood), anaemia, and kernicterus. Perinatal loss due to Rh isoimmunization has been reported to be between 1% and 2.5%.

Preventing Rh isoimmunisation

Though preventable by preventing sensitization of Rh-Negative women, Rh isoimmunisation continues to account for 97% of haemolytic disease of the new-born (HDN). Prevention can be achieved by Rh immunoglobulin (Rhlg) injection at any potentially sensitizing event such as spontaneous miscarriage, termination of pregnancy, ectopic pregnancy, external cephalic version, ante-partum haemorrhage etc. and secondly, post-natal Rh prophylaxis in all Rh-negative women delivering a Rh-positive baby within 72 hours. Unfortunately, Rh isoimmunisation continues to be a significant health problem in India.

Once pregnancy happens in a sensitized woman, development of HDFN and its consequences can be prevented today by close supervision, timely diagnosis by maternal antibodies against Rh D, and fetal monitoring; and then intra-uterine transfusion when needed. However, in India, preventive therapy in the form of anti-D immunoglobulin remains highly underutilized and even today, a large number of women in need do not receive Anti-D immunoglobulin. A study found that only 34% of patients had received Anti – D immunoglobulin prophylax treatment in previous pregnancies. The reason why they did not receive anti-immunoglobulin was either lack of awareness, home delivery or the cost factor.

Treating the condition

In the case of Rh-incompatible pregnancies, an Indirect Coombs’ test (ICT) is conducted periodically to check for the development of anti-bodies in the mother. If ICT is negative, Rh immunoglobulin (Rhlg) injection is given at all the potentially sensitizing events mentioned above. However, if ICT is positive (implying antibodies have already developed), the fetus needs to be monitored regularly with close surveillance by USG and Doppler studies. In some cases, an intrauterine blood transfusion may be needed if the baby is found to be severely anaemic.

It is important, therefore, to ensure that all pregnant women are screened for their blood groups and Rhesus status, the possibility of Rh incompatibility and timely medical intervention is introduced where needed.